hot-dip galvanized

Steel hot dipped galvanized

for purely technical surfaces

In hot-dip galvanizing, the steel base material is immersed in a molten zinc bath (approx. 450°C). After dripping, a more or less thin zinc layer remains as a coating. This forms both active and passive corrosion protection: the thin layer protects the base metal from moisture (passive) and also acts as a sacrificial anode (active). The steel under the zinc coating is protected from corrosion until the zinc is completely consumed. The zinc coating is bright shiny when fresh. Over time, as a result of corrosion, it develops a patina, which makes the appearance darker and duller.

Hot-dip galvanizing is a cost-effective way to achieve a surface that is durable but purely technical, because the main purpose of hot-dip galvanizing is solely to protect against corrosion. Requirements for the aesthetics of the surfaces are not defined. In order to avoid complaints, we therefore strongly recommend that metal objects which have to meet visual requirements are additionally or alternatively finished with a color-coated surface.

Earth retaining wall TERRA PALA made of hot-dip galvanized steel
Seat steps with TERRA PALA earth retaining wall made of hot-dip galvanized steel

Everything important at a glance.

STEEL hot dipped galvanized

Information material

User information METAL

Tender for basic material

Color coating

for hot-dip galvanized objects?

Even hot-dip galvanized objects can be coated with paint. To ensure that the paint adheres well, an adhesion improver (primer) is usually applied beforehand. However, whether the primer has actually been applied to the complete hot-dip galvanized surface is difficult to check after paint coating and often only becomes apparent after years due to rust spots. We therefore recommend that garden objects that are to be color-coated be made of the corrosion-resistant base material stainless steel (V2A). This is not the cheapest option, but certainly the most durable.

Environmental aspects

speak for hot dip galvanizing

Corrosion protection by hot-dip galvanizing is resource-saving and sustainable. In direct comparison to other processes, a large amount ofCO2 is saved.

Bicycle parker OLDENBURG made of hot-dip galvanized steel, support made of hardwood
Bicycle parker OLDENBURG made of hot-dip galvanized steel, crossbar made of hardwood

Layer thickness according to ISO standard

All our hot-dip galvanized garden objects are treated according to the requirements of DIN EN ISO 1461. This guarantees a minimum coating thickness of 55 μm for material thicknesses between 3 mm and 6 mm, and even a coating thickness of 70 μm for sheet thicknesses greater than 6 mm. At these thicknesses, depending on the environmental conditions, a service life of more than 50 years can be achieved without maintenance due to the passive and active protective effect of the zinc coating.

Problem: White rust on hot-dip galvanized surfaces

White rust is the name given to streaky corrosion phenomena on the hot-dip galvanized surface. White rust has no effect on weather resistance, but makes the garden object unsightly. To reduce white rust formation, many hot-dip galvanizers offer additional protective coatings for the hot-dip galvanized surface. However, this is relatively expensive and is actually not necessary if the freshly galvanized objects are treated and stored properly. Therefore, an additional protective coating is not standard and may have to be agreed and ordered separately.

White rust formation

White rust can form if the freshly galvanized objects are stored on site under unfavorable weather conditions or temporary exclusion from the air and at the same time come into contact with water, in particular with condensation water with a low mineral content. Dew point undershoots and low temperatures also promote the formation of white rust. The classic case is: the objects stand in the rain under a protective film in spring or autumn, waiting for installation. Then the unsightly white rust can form after just a few hours!

White rust removal

The white rust can be removed again under various circumstances. The faster the reaction after formation, the easier the removal. White rust can be removed mechanically with hard nylon brushes. The processed surfaces are rinsed with plenty of water. Metal wire brushes are not suitable, as they create scratches in the soft zinc coating layer.

White rust formation with hot-dip galvanizing on the surface on a bench seat
Bicycle parker OLDENBURG made of hot-dip galvanized steel, crossbar made of hardwood

Tender text for GaLaBau, for landscape architects and planners

“Rolled flat steel with corrosion protection by hot-dip galvanizing (piece galvanizing) in accordance with DIN EN ISO 1461: 2009-10. For load-bearing, hot-dip galvanized metal and steel components in the area regulated by building authorities, DASt Guideline 022 “Hot-dip galvanizing of load-bearing steel components” shall also be applied.”
The thickness of the zinc coating does not have to be specified separately, as this is regulated in DIN EN ISO 1461.

Attention sign

For the best possible protection against white rust, we recommend additional sealing of the hot-dip galvanized surface directly ex works during hot-dip galvanizing. This is a separate service outside of DIN EN ISO 1461 and must therefore be agreed additionally. Suggested text: “With additional protective coating for increased protection against white rust after hot-dip galvanizing.”

Everything important at a glance.

STEEL hot dipped galvanized

Information material

User information METAL

Tender for basic material